On Wed, 15 Apr 2020 12:24:42 Michal Hocko <mhocko@xxxxxxxxxx> wrote: > On Wed 15-04-20 12:17:53, Bruno Prémont wrote: > [...] > > > Anyway the following simply tracing patch should give a better clue. > > > The output will appear in the trace buffer (mount tracefs and read > > > trace_pipe file). > > > > This is the output I get on 5.6.4 with simple tar -zc call (max=high+4096): > > tar-16943 [000] .... 1098.796955: mem_cgroup_handle_over_high: memcg_nr_pages_over_high:1 penalty_jiffies:200 current:262122 high:262144 > > tar-16943 [000] .... 1100.876794: mem_cgroup_handle_over_high: memcg_nr_pages_over_high:1 penalty_jiffies:200 current:262122 high:262144 > > tar-16943 [000] .... 1102.956636: mem_cgroup_handle_over_high: memcg_nr_pages_over_high:1 penalty_jiffies:200 current:262120 high:262144 > > tar-16943 [000] .... 1105.037388: mem_cgroup_handle_over_high: memcg_nr_pages_over_high:1 penalty_jiffies:200 current:262121 high:262144 > > tar-16943 [000] .... 1107.117246: mem_cgroup_handle_over_high: memcg_nr_pages_over_high:1 penalty_jiffies:200 current:262122 high:262144 > > OK, that points to the underflow fix. > > > > > With 5.7-rc1 it runs just fine, pressure remains zero and no output in trace_pipe or throttling. > > > > So the fixes that went in there do fix it. > > Now matter of cherry-picking the right ones... e26733e0d0ec and its fixe's fix, > > maybe some others (will start with those tagged for stable). > > I have seen Greg picking up this for stable trees so it should show up > there soon. Applying just 9b8b17541f13809d06f6f873325305ddbb760e3e which went to stable-rc for 5.6.5 gets things running fine where. (e26733e0d0ec seems to have gone in shortly prior to 5.6 release, need to improve my git-foo to locate commits between tags!) So yes it's the fix. Thanks, Bruno > Thanks!
